The disclosure relates to a hydraulic dual axial piston machine having a first drive unit and having a second drive unit which are arranged one behind the other in the direction of the axis of a drive shaft and so as to be oriented oppositely to one another. The first drive unit is equipped with a first swashplate, which for the purpose of varying the inclination relative to the axis of the drive shaft can be pivoted about a first pivot axis, and with a single first actuating piston, which extends at least approximately parallel to the axis of the drive shaft and which, at a first end, engages on the first swashplate for the purpose of pivoting the latter in one direction and which, at a second end, delimits an actuating chamber into which control fluid flows for the purpose of pivoting the first swashplate in one direction and out of which control fluid can be displaced in the event of a pivoting movement of the first swashplate in the other direction. The second drive unit is equipped with a second swashplate, which for the purpose of varying the inclination relative to the axis of the drive shaft can be pivoted about a second pivot axis parallel to the first pivot axis, and with a single second actuating piston, which extends at least approximately parallel to the axis of the drive shaft and which, at a second end, engages on the second swashplate for the purpose of pivoting the latter in a functionally identical manner to the first actuating piston on the first swashplate and which, at a second end, delimits an actuating chamber into which control fluid flows for the purpose of pivoting the second swashplate in one direction and out of which control fluid can be displaced in the event of a pivoting movement of the second swashplate in the other direction.
A dual pump of said type, with a back-to-back arrangement of the two component pumps, is known from practice and from the repair manual RDE 93100-11-R/07/07 from Bosch Rexroth AG. Here, the two regulating valves for the adjustment of the component pumps are arranged, on a central part of the housing, in the same plane and so as to be offset both in the longitudinal direction and also in a transverse direction. Furthermore, the regulating valves are oriented oppositely to one another, such that for each regulating valve, the arrangement with respect to the component pump with which it is associated is the same. The actuating pistons are also offset with respect to one another as viewed perpendicularly to the longitudinal direction of the dual pump. This means that the position of the actuating pistons with respect to the exertion of force on the two swashplates by the pump pistons presently performing a delivery stroke is different in the case of one swashplate than in the case of the other swashplate.
The disclosure is based on the object of further developing a hydraulic dual axial piston machine of the known type such that substantially identical conditions are present with regard to the two drive units.
This is achieved in that the first actuating piston and the second actuating piston, which exert load on the pivot cradle in a functionally identical manner and which thus either both act in the direction of an increase or both act in the direction of a decrease in the pivot angle of the respective swashplate, are arranged, so as to be spaced apart from a central plane of the swashplates which is perpendicular to the pivot axes and which extends through the axis of the drive shaft, at least approximately in alignment with one another. Identical conditions thus prevail for both drive units with regard to the locations at which force is exerted on the swashplates by the pump pistons and by the first and second actuating pistons. As a result of the arrangement spaced apart from a plane which is perpendicular to the pivot axes and which extends through the axis of the drive shaft, the actuating pistons are situated within the housing in such a region that the maximum dimensions of the housing in the direction of the pivot axes of the swashplates, and perpendicular thereto, are influenced at most to a small extent.
Advantageous embodiments of a hydraulic dual axial piston machine according to the disclosure emerge from the description below.